KR20150140694A - Near-eye device - Google Patents

Abstract

Thereby providing a spectacular device for enhancing an actual sight. The spectacular apparatus includes a spatial light modulator including an array of phase modulation elements arranged to apply a phase retardation distribution to the incident light. The apparatus also includes a beam synthesizer including a first optical input adapted to receive light spatially modulated from the spatial light modulator and a second optical input having an actual field of view.

Description

[0001] NEAR-EYE DEVICE [0002]

This disclosure relates to the field of near-eye devices, such as goggles and glasses, which are used close to the eye. The embodiments disclosed herein relate generally to a spectacular apparatus for augmenting or augmenting reality of a real scene. More specifically, the embodiments disclosed herein generally relate to holographic projection for augmented reality, including phase-limited hologram projection technology for augmented reality.

Eyeglass devices are being developed for the same purpose as augmented reality.

A known spectacled apparatus is shown in Fig. Figure 1 shows illumination of the spatial light modulator 107 through a beam splitter 105 by means of an array of light sources 101 and a collimating lens 103. The spatial light modulator 107 includes an array of amplitude modulation elements arranged to form an image. More specifically, the amplitude of the light incident on the spatial light modulator 107 is spatially modulated to form an image. The image can be viewed through the beam splitter 105. More specifically, the image on the spatial light modulator 107 forms the first light input 121 of the beam combiner 109. The beam synthesizer 109 also includes a second optical input 123 that provides a real scene of a constant field of view.

The beam synthesizer 109 has a spherical surface 111 so that the image of the spatial light modulator 107 is diverged. The beam synthesizer 109 is also configured to at least partially reflect the diverging image to the optical output 125 of the beam combiner.

The light received at the second optical input 123 also travels towards the optical output 125 of the beam synthesizer 109. From this point of view, it can be understood that the beam synthesizer combines the image emitted by the spatial light modulator 107 with the actual image. Therefore, it can be seen that the actual image is enhanced by the image in the spatial light modulator. It should be noted that the apparatus described with reference to Figure 1 provides a spherical surface 111 so that the image on the spatial light modulator appears to come from some fixed point in the space behind the beam combiner. Thus, the image from the spatial light modulator 107 appears to come from some fixed point in the space defined by the radius of curvature of the spherical surface 111.

SUMMARY OF THE INVENTION The present disclosure is directed to providing an improved spectacular device.

Aspects of the invention are defined by the appended independent claims.

A spectacular apparatus and a corresponding method are provided using a beam combiner arranged to receive spatially modulated light from a spatial light modulator and to provide an actual field of view. In this way, the actual scene can be supplemented or enhanced by additional information in the form of an image. Known eyeglass devices use physical optics to project an actual image onto the scene to add eye relief.

According to an aspect of this embodiment, there is provided a spatial light modulator including an array of phase modulation elements arranged to apply a phase retardation distribution to incident light; And a beam synthesizer comprising a beam splitter comprising a first optical input adapted to receive spatially modulated light from the spatial light modulator, i.e. a spatially modulated light, and a second optical input having an actual field of view.

Also, there is provided a method of providing an augmented reality using a spectacle-type apparatus, comprising: providing hologram data including phase-limited hologram area data representing an image; Spatially modulating light with the hologram data to form spatially modulated light, i.e., spatially modulated light; And combining the actual view and the spatial modulated light using a beam synthesizer.

The present invention has an effect of providing images by a hologram technique using a computer.

This technology is more energy efficient and allows to encode or embed additional optical elements in the imaging data.

As another effect, no complicated additional parts are required.

As another effect, the distance of the enhancement image can be controlled in real time.

Embodiments will be described with reference to the accompanying drawings.
1 is a schematic view of a known eyeglass device.
Figure 2 shows a schematic diagram of a reflective spatial light modulator (SLM), such as liquid crystal on silicon (LCOS), configured to generate a hologram reconstruction at a replay field location will be.
3 is a diagram showing an exemplary algorithm for creating a phase-only hologram by a computer.
4 is a diagram illustrating an exemplary random phase seed for the example algorithm of FIG.
5 is a diagram showing an embodiment according to the present disclosure.
6 is an algorithm for calculating a Fresnel hologram according to an embodiment.
7 is a schematic diagram of an LCOS SLM.
In the drawings, like reference numerals refer to like parts.

It is an object of the present invention to provide an improved spectacled apparatus by solving some of the disadvantages of the prior art apparatus using a beam synthesizer with a molding surface utilizing an image on a spatial light modulator and adding a so-called eye relief. In particular, the present invention recognizes that the improved spectacles device can be provided using multipurpose computer-assisted hologram techniques.

The light scattered by the object contains both amplitude and phase information. The amplitude and phase information may be captured on a photosensitive plate, for example, by known interferometry to form a hologram recording or " hologram " that includes interference fringes. A "hologram" may be illuminated with appropriate light and reconstructed to form a hologram reconstructed or reconstructed image representing the original object.

It has been found that an acceptable quality hologram reconstruction can be made in a "hologram" that includes only the phase information associated with the original object. Such hologram recording may be referred to as phase-limited hologram. Computer generated holography may, for example, use Fourier techniques to numerically simulate the interference process to generate a computer generated phase-limited hologram. Computer generated phase-limited holograms can be used to generate a hologram reconstruction that represents an object.

Thus, the term "hologram" relates to a record that can contain information about an object and which can be used to form a reconstruction representing the object. The hologram may contain information about an object in the frequency domain or the Fourier domain.

It has been proposed to use hologram technology in a two-dimensional image projection system. The advantage of image projection using phase-limited holograms is the ability to control many image attributes, such as aspect ratio, resolution, contrast, and dynamic range, of projected images through computerized methods. An additional advantage of phase-limited holograms is that there is no loss of light energy through amplitude modulation.

The computer-formed phase-limited hologram may be "pixellated ". That is, the phase-limited hologram may be displayed on an array of discrete phase elements. Each discontinuous element can be represented by "pixel ". Each pixel can act as a light modulation element like a phase modulation element. Thus, a phase-limited hologram formed by a computer can be displayed on an array of phase modulation elements, such as a liquid crystal spatial light modulator (SLM). The SLM can be said to be reflective in the sense that modulated light is output from the SLM by reflection.

Each phase-modulating element, i. E., The pixel, can be in a different state to provide a phase delay that can control the light incident on the phase-modulating element. Thus, an array of phase modulation elements, such as a liquid crystal liquid crystal (LCOS) SLM, can be represented (or "displayed") with a determined phase delay distribution. If the light incident on the array of phase modulation elements is coherent, the light will be modulated with hologram information, or holograms. The hologram information may be in frequency, i. E. In the Fourier domain.

Alternatively, the phase delay distribution can be recorded on a kinoform. The term "chinofoam" may be used generically to refer to phase-limited hologram recording or holograms.

The phase delay can be quantized. That is, each pixel can be set to one of a discrete number of phase levels.

The phase delay distribution can be applied to the incident light wave (e. G., By illuminating the LCOS SLM) and can also be reconstructed. As a result, the spatial position of the reconstruction can be controlled by performing a Fourier transform lens using a lens to form a hologram reconstruction, or "image ", in the spatial domain. Alternatively, a lens may not be needed if the reconstruction occurs in a far-field.

Computer-generated holograms can be computed in a variety of ways, including using algorithms such as Gerberberg-Saxton. The stationary bug-color stun algorithm can be used to derive the phase information of the frequency domain from the amplitude information of the spatial domain (e.g., two-dimensional image). That is, the phase information about the object may be "retrieved " from intensity or amplitude, which is the only information in the spatial domain. Thus, a phase-limited hologram that represents an object in the frequency domain can be computed.

The formation of the hologram reconstruction is possible, for example, by irradiating a hologram using a Fourier transform lens to form an image (hologram reconstruction) in a reproduction field such as a screen or performing an optical Fourier transform as necessary. In the case of the Fresnel hologram, the hologram reconstruction is formed at a predetermined position.

Figure 2 illustrates an example of using a reflective SLM, such as an LCOS-SLM, to generate a Fourier hologram reconstruction at a playback field location, in accordance with the present disclosure.

A light source 210, such as a laser or a laser diode, is arranged to illuminate the SLM 240 through a collimating lens 211. The collimating lens allows a nearly planar light wavefront to be incident on the SLM. The direction of the wavefront is slightly off-normal, for example at an angle of 2 or 3 degrees away from the plane perpendicular to the plane of the SLM transparent layer. With this arrangement, the light from the light source is reflected on the mirror on the rear side of the SLM and interacts with the phase modulation layer to form an exiting wavefront 212. [ The exit wavefront 212 is applied to an optical system including a Fourier transform lens 220 focused on the screen 225.

The Fourier transform lens 220 receives the beam of phase modulated light emerging from the SLM and performs a frequency-to-space transformation to produce a hologram reconstruction in the screen area 225 of the spatial domain.

In this process, in the case of a light-image projection system from a light source, visible light-is distributed over the SLM 240 and the phase modulation layer (i.e., the array of phase modulation elements). The light emitted from the phase modulation layer can be distributed over the reproduction field. Each pixel of the hologram contributes to the reconstructed image as a whole. That is, there is no one-to-one correlation between the specific point of the reproduced image and the specific phase modulation element.

Considering the phase restoration problem through bug-color Stern algorithm of I _A (x, y) and I _B (x, y) the intensity cross-sectional area (intensity cross-section) of the light beam on the respective surfaces A and B of the base Values and are correlated by a single Fourier transform. Given the strength cross-sectional area, the approximate values of φ _A (x, y) and φ _B (x, y), which are the respective phase distributions in planes A and B, are obtained. The mounting bug-color stun algorithm finds the solution to this problem by performing an iterative process.

The stationary bug-color stun algorithm repeatedly transmits data sets (amplitude and phase) represented by I _A (x, y) and I _B (x, y) between the spatial domain and the Fourier iteratively applying space and spectral constraints. The spatial and spectral constraints are I _A (x, y) and I _B (x, y), respectively. Constraints in the spatial or spectral region are imposed on the amplitude of the data set. The corresponding phase information is retrieved through a series of iterations.

A modification algorithm based on a staggered bug-color stunner has been developed and is described, for example, in co-pending patent application WO 2007/131650, which is incorporated herein by reference.

Figure 3 shows a modified algorithm for retrieving the phase information [[u, v]] of the Fourier transform of the data set generating the known amplitude information T [x, y] The amplitude information T [x, y] 362 represents a target image (e.g., a photograph). And generates a hologram representing the target image in the image plane using the phase information [P, u, v].

Since the magnitude and phase are inherently combined in the Fourier transform, the transformed magnitude (and phase) contains useful information about the accuracy of the computed data set. Thus, the algorithm can provide feedback for both amplitude and phase information.

The algorithm shown in Fig. 3 has a complex wave input (including amplitude information 301 and phase information 303) and a complex wave output (also including amplitude information 311 and phase information 313) Can be considered. For convenience of explanation, amplitude and phase information are considered separately, although they are essentially combined to form a data set. It is important to remember that both amplitude and phase information are themselves functions of spatial coordinates (x, y) for farfield images and (u, v) for holograms, both amplitude and phase distributions.

According to FIG. 3, processing block 350 generates a Fourier transform from a first set of data having magnitude information 301 and phase information 303. The result is a second set of data with magnitude information and phase information [n, u, v] 305. The amplitude information of the processing block 350 is set to a distribution representing a light source, but the phase information [n, u] 305 is maintained. The phase information 305 is quantized by the processing block 354 and output as phase information [n, u] 309. The phase information 309 is passed to the processing block 356 and combined with the new size by the processing block 352. The third data set 307, 309 is input to a processing block 356 which performs an inverse Fourier transform. Thus, a fourth data set R _n [x, y] having amplitude information 311 and phase information 313 is generated in the spatial domain.

Starting with the fourth data set, the phase information 313 of the fourth data set forms the phase information of the fifth data set that is input to the first data set of the next iteration 303 '. The amplitude information 315 is modified by modifying the amplitude information R _n [x, y] 311 by the amount of the amplitude information T [x, y] 362 of the target image to generate the set of amplitude information 315. The input amplitude information? [X, y] 301 of the fifth data set is subtracted from the target amplitude information T [x, y] 362, which is scaled amplitude information 315 And applies it to the next iteration as a first set of data. It is mathematically expressed as:

here:

F 'is an inverse Fourier transform

F is a forward Fourier transform

R is the playback field

T is the target image

∠ is angle information

Ψ is the quantized version of the angular information

? is the new target size, and? 0.

α is ~ 1 as a gain factor.

The gain element? Can be predetermined according to the size and speed of the received target image data.

In the absence of phase information from the preceding iterative process, the first iteration of the algorithm uses a random phase generator to provide random phase information as a starting point. Figure 4 shows an example of a random phase seed.

In a variation of the invention, the resulting amplitude information received from the processing block 350 is not deleted. The target amplitude information 362 is subtracted from the amplitude information to generate new amplitude information. A multiple of the amplitude information is subtracted from the amplitude information 362 to generate input amplitude information for the processing block 356. As another alternative, the phase is not fed back in its entirety, but a portion proportional to the changed through the last two iterations is fed back.

In this manner, the Fourier domain data representing the image of interest can be formed.

By way of example only, the embodiments related to the phase hologram will be equally applicable to amplitude holograms.

The present inventors have recognized the limitations of the spectacles apparatus shown in Figure 1:

The apparatus of Figure 1 is energy inefficient because the light is amplitude modulated, including the process of attenuating most of it.

- Images that augment the actual scene are recognized at fixed (ie, non-variable) locations of space.

- Additional optical systems may be required to compensate for optical aberrations of optical components.

It is also expensive to produce spheres as part of the synthesizer.

The present inventors solve this problem by using a multipurpose holography technique to form an image that enhances a real scene. This image may be called an " augmenting image ".

Figure 5 shows an embodiment of the present invention.

The light source 501 and the condenser lens 503 are arranged to illuminate the spatial light modulator 507 through the beam splitter 505. Spatial light modulator 507 includes an array of phase modulating elements (or "pixels") arranged to display (or "display") a hologram area representation of the image. More specifically, the phase of the light incident on the spatial light modulator 507 is spatially modulated to form spatial modulated light. This spatial modulated light forms the first light input of the beam synthesizer 509.

The beam synthesizer 509 includes a second light input 523 that provides a real scene of a certain field of view. Further, the beam splitter 505 is configured so as to move the space-modulated light toward the light output 525 of the beam synthesizer 509. From this perspective, it can be understood that the beam synthesizer combines the actual image with the spatial modulated light. Therefore, it can be seen that the actual image is enhanced by the light emitted from the spatial light modulator.

It will be readily appreciated that the beam splitter 505 is optional and that the spatial light modulator 507 may be illuminated with other geometries that receive a backlight for the same result or that do not require a beam splitter. Those skilled in the art will also appreciate that other techniques for collimating light may also be used.

In contrast to the apparatus described with reference to FIG. 1, the spatial light modulator 507 according to the present disclosure spatially modulates the phase, not the amplitude, of the incident light. This makes the device more energy efficient because the light is not attenuated.

The spectacular apparatus thus provided comprises a spatial light modulator comprising an array of phase modulation elements arranged to apply a phase retardation distribution to the incident light; And a beam combiner comprising a first optical input adapted to receive spatially modulated light from the spatial light modulator, i.e., a spatial modulated light, and a second optical input having a real field of view.

In contrast to the apparatus of FIG. 1, the spatial light modulator 507 displays a hologram corresponding to an image rather than an actual image. That is, the spatial modulated light includes phase-limited hologram area data representing an image. Thus, this device is energy efficient because all parts of the hologram contribute to all parts of the reconstruction.

In an embodiment, the hologram is a Fourier hologram. That is, the hologram area data is a Fourier hologram. A Fourier hologram is a hologram whose reconstruction is formed at infinity or at the focus of a lens that performs Fourier transform. Advantageously, by using a Fourier hologram, the observer's eye can perform a Fourier transform to form a hologram reconstruction in the retina. Thus, the distance between the observer and the beam synthesizer is not critical. That is, the observer can see the hologram reconstruction as it is, even when moving toward or away from the beam synthesizer. Thus, the device is more stable and more flexible to the observer's movement. That is, in the embodiment, the spatial modulated light enables the user's eyes to see the hologram reconstruction of the image while performing the Fourier transform of the spatially modulated light.

The embodiments described herein with respect to a Fourier hologram are merely illustrative. The present disclosure is equally applicable to a Fresnel hologram applied to a Fresnel lens function in hologram calculation. Fig. 6 shows an example of a Fresnel hologram algorithm for calculating Fourier domain data representing a target image for projection.

The start condition 601 for the phase reconstruction algorithm is that each pixel has a random phase provided by a random phase seed function while having a single amplitude (unity amplitude). And adds the Fresnel phase function 603 to the phase data. The obtained amplitude and phase functions are Fourier transformed (605). The target image or the target image (amplitude limitation) 609 is subtracted from the amplitude component and the applied controllable gain 611. The target image 609 is added to the amplitude component, and inverse Fourier transform 615 is performed. Subtracts the Fresnel lens function 717, and quantizes (619) the phase. The obtained phase information forms a hologram 623. The Fresnel lens function 621 is added again to perform an additional iterative loop of this loop and the Fourier transform 615 and subsequent steps are repeated until a hologram of "acceptable" quality is obtained.

In an embodiment, the hologram is a Fresnel hologram. That is, the hologram area data is a Fresnel hologram. In the Fresnel hologram, a hologram reconstruction is formed at some predetermined point along the Fourier path. That is, in the embodiment, the spatial modulated light is such that it forms a hologram reconstruction of the image on the reproduction surface in the near-field. Advantageously, a Fresnel hologram can create a reconstruction in multiple planes of space from a single hologram. Therefore, a plurality of images can simultaneously enhance a real scene.

In an embodiment, the hologram further comprises lensing data. Specifically, hologram area data having a lensing effect is added to (e.g., added to) hologram area data representing an image. This additional hologram data imitates an actual lens, and thus adds optical power. Thereby, the lens effect data controls the position at which the image will appear to the user in space. Methods of computing hologram area data with the required lens effect and how to add such data to other hologram area data are known to those skilled in the art.

Thus, in one embodiment, the spatial modulated light further comprises phase limited hologram area data having a lens effect.

In an embodiment, the hologram is a phase-limited hologram and the lens effect is provided by a phase-limited lens. Phase-limited holograms can be computed in real time or retrieved from a repository such as a database. The hologram may be computed using a stationary bug-color stun algorithm or any other algorithm for generating the appropriate hologram area data. It will be appreciated by those of ordinary skill in the art that the hologram may be an amplitude hologram or an amplitude and phase hologram, so that the lens effect is provided by amplitude holograms or amplitude and phase holograms.

In the embodiment, the hologram area data representing the image is combined with the hologram area data having the lens effect so that additional elements such as the spherical surface of the beam synthesizer, for example, are not needed when adding the eye relief to the system. As a result, the manufacturing cost of the system is reduced. In particular, the cost of manufacturing the spherical surface within the required tolerance range is high.

In one embodiment, the two sets of hologram data are combined by simple vector addition. In this regard, the hologram displayed on the spatial light modulator includes first data representing a real image to be enhanced and second data including a lensing function. In particular, the lens effect function can be simply changed by merely adding another lens effect function to the hologram data representing the image. Thus, this method enables, for example, real-time adjustment of the perceived position of the image when the system is reordered in use or when the user wishes to display data at various distances.

In one embodiment, the lens effect is a negative lens effect. Therefore, the image enhancing the actual scene has the effect of moving away from the user. That is, the image appears to appear at the origin farther than the actual origin. Specifically, it seems that the image comes from a point farther from the spatial light modulator. From this perspective, it can be said that the lens effect adds eye relief. Preferably, by using the negative lens effect, the image can be displayed to the user as much as it is within the range of the actual scene. In other words, in one embodiment, the spatial modulated light is diverged.

In another embodiment, additional optical power can be added to the hologram to compensate for other optical components. In one embodiment, the spatial modulated light further comprises phase limited hologram area data adapted to correct aberrations in other optical components of the device. It is also understood that phase-limited hologram area data adapted to compensate for aberrations are numerically controlled and can be easily changed.

From the above description, it can be understood that the image (hologram reconstruction) enhances the actual scene in the embodiment. This enhancement in the embodiment is achieved optically. In one embodiment, the first optical input and the second optical input are co-linear. In one embodiment, the beam synthesizer further comprises a light output adapted to combine the light received at the first light input with light at the second light input. Thus, an easy and convenient way to augment the actual scene with the image is provided. Specifically, in one embodiment, the light output is such that the light received at the first light input is at least partially overlapped with the light received at the second light input.

In one embodiment, the spectacular device is configured to allow the user to receive light output from the beam synthesizer. Hologram reconstruction can be used to provide additional information to the user. The hologram configuration can also be used to provide an artificial scene. In one embodiment, hologram reconstruction of the image enhances the actual field of view.

It is to be understood that the apparatus requires a light source, but the light source may be external to the spectacles apparatus or may instead be integral with the spectacles apparatus. In one embodiment, the spectacular apparatus further comprises a light source adapted to illuminate the spatial light modulator.

Simply incident light can be a flat file. However, it can be seen that the hologram can be adjusted to the incident light to generate the light necessary to form the desired image, and to reconstruct the desired image after spatial modulation. That is, the incident light may not be a plane wave. However, in one embodiment the light source is configured to illuminate the spatial light modulator with a plane wave of light.

In one embodiment, the spectacled device is a goggle or a pair of glasses. Those skilled in the art will appreciate that the spectacular device may take other known forms. The image may be a video image and may be time-variant. The video can move with time. The image may also be a still image.

There is provided a method of providing an augmented reality using a spectacular device, the method comprising: providing hologram data comprising phase limited hologram area data representing an image; Spatially modulating light with hologram data to form spatially modulated light, i.e., spatially modulated light; And synthesizing the actual view and the spatial modulated light using a beam synthesizer. In one embodiment, the hologram data further includes phase limited hologram area data having a lens effect. In one embodiment, the hologram area data is at least one of a Fourier hologram and a Fresnel hologram.

The light can be spatially modulated using a spatial light modulator such as a liquid crystal SLM on silicon. The hologram data is recorded in the SLM, and the incident plane wave of the light is spatially modulated by the hologram data. In this regard, it can be seen that the pixels of the SLM are "displaying" or "displaying" the hologram data.

It can be seen that this device can display various information. Thus, the hologram corresponding to a plurality of displayable images can be pre-calculated and stored in a storage or can be calculated in real time. In one embodiment, a repository of hologram area data representing a plurality of images, respectively, is provided. Likewise, in the embodiment, a storage of hologram area data having various lens effects is provided. In another embodiment, a look-up table of optical power of various lensing data sets is provided.

The quality of the reconstructed image in the Fourier hologram can be affected by the so-called zero order problem, which is the result of the diffraction characteristics of the reconstruction. This zero order light can be considered "noise" and can include, for example, regularly reflected light and other unwanted light from the SLM.

This "noise" is generally adjusted to the focal point of the Fourier lens, resulting in a bright spot at the center of the reconstructed image. Typically, the zeroth order light is simply blocked, but this means replacing the bright spot with a dark spot.

However, since the hologram contains three-dimensional information, it is possible to reposition the reconstruction to another plane of space. See, for example, PCT Application Publication No. WO 2007/131649, which is incorporated herein by reference.

Alternatively, the angle selective filter can be used to remove only the zeroth order of parallel rays. Other methods of managing the zeroth order can also be used.

Although the embodiments described herein display one image per frame, the present disclosure is not limited in this respect, and one or more holograms may be displayed on the SLM at any one time.

For example, embodiments implement a "tiling" technique to further subdivide the surface area of the SLM into multiple tiles and set each tile in a phase distribution similar or identical to the original tile. Thus, the surface area size of each tile is smaller than if the entire assigned area of the SLM was used as one large phase pattern. The smaller the number of frequency components in the tile, the greater the distance that the reconstructed pixels are spaced apart as the image is generated. Since the image is generated in the 0th-order diffraction order, it is preferable to change the positions of the first and subsequent orders sufficiently far so as not to overlap with the image, and it is also possible to block the space between them.

As described above, an image generated by this method (regardless of whether or not tiling is used) includes a spot forming an image pixel. The greater the number of tiles used, the smaller the point. As an example of the Fourier transform of an infinite sinusoid, a single frequency is generated. This is the optimal output. In practice, if only one tile is used, this corresponds to the input of a sinusoidal wave in a single cycle, such that the zero values lead infinitely in positive and negative directions from the end nodes of the sinusoidal wave. Instead of generating a single frequency from its Fourier transform, a main frequency component and a series of adjacent frequency components on both sides thereof are generated. The use of tiling reduces the magnitude of these adjacent frequency components and, as a direct consequence thereof, can improve image quality by reducing interference (enhancement or offset) between adjacent image pixels.

Although it is possible to use a portion of the tile, preferably each tile is a whole tile.

While the embodiments relate to a modification of the embedding bug-color stun algorithm, one of ordinary skill in the art will appreciate that other phase reconstruction algorithms may implement the improved methods disclosed herein.

It will be appreciated by those of ordinary skill in the art that the improved method disclosed herein may equally be applied to the calculation of a hologram used to form a three-dimensional reconstruction of an object.

Likewise, the present invention is not limited to the projection of monochromatic images.

Two-dimensional color hologram reconstruction can also be generated, and there are two main ways to achieve this. One of these is known as "frame-sequential color" (FSC). The FSC system uses three lasers (red, green, blue), and each laser is fired continuously in the SLM to produce each frame of video. Color is circulated (red, green, blue, red, green, blue, etc.) at a sufficiently fast rate, allowing viewers to view multicolor images from a combination of three lasers. Thus, each hologram corresponds to a specific color. For example, in a video of 25 frames per second, the generation of the first frame is generated by a green laser firing for 1/75 second after the red laser firing for 1/75 second and a blue laser firing for the last 1/75 second . Then, the next frame is generated, starting with a red laser, and so on.

Alternatively, "spatially separated colors " (SSC), described below, may be used to simultaneously emit all three lasers, but to take different optical paths, for example, each laser using a different SLM or a single SLM Another area is used, and then combined to form a color image.

The advantage of the frame-sequential color (FSC) approach is that a full SLM is used for each color. This means that since all the pixels of the SLM are used for each color image, the image quality of the generated three color images is not impaired. On the other hand, the disadvantage of the FSC method compared to the SSC method is that the overall image generated is three times as dark as the corresponding image generated by the SSC method because each laser uses only 1/3 of the time. This disadvantage can potentially be overcome by overdriving the laser or using a stronger laser, but it requires more power and makes it more difficult to produce a system with high cost and compactness.

The advantage of the space-separated color (SSC) approach is that the images are brighter because the three lasers are fired at the same time. However, if only one SLM is required due to space constraints, the surface area of the SLM is equally divided into three equal parts to obtain the effect of three individual SLMs. However, the disadvantage of this is that the image quality of each single color image is reduced due to the reduction of the SLM surface area available for each monochrome image. As a result, the image quality of the multicolor image deteriorates. As the available SLM surface area is reduced, only fewer pixels on the SLM can be used, so image quality is reduced. Since the resolution is reduced, the image quality is also reduced.

In an embodiment, the SLM is a liquid crystal over silicon (LCOS) device. The advantage of LCOS SLM is that signal lines, gate lines, and transistors are below the mirror surface, resulting in high fill factors (typically 90% or more) and high resolution.

The LCOS device is now available in pixels between 4.5 and 12 micrometers.

The structure of the LCOS device is shown in Fig.

The LCOS device is formed using a single crystal silicon substrate 802. [ The LCOS device has a two-dimensional array of square-planar aluminum electrodes 801 spaced apart by a gap 801a on the upper surface of the substrate. Each of the electrodes 801 may be addressed through a circuit 802a buried in the substrate 802. [ Each electrode forms a respective plane mirror. An alignment layer 803 is disposed on the electrode array and a liquid crystal layer 804 is disposed on the alignment layer 803. [ A second alignment layer 805 is disposed on the liquid crystal layer 804 and a planar transparent layer 806 made of glass is disposed on the second alignment layer 805, for example. For example, a single transparent electrode 807 made of ITO is disposed between the transparent layer 806 and the second alignment layer 805.

Each of the square electrodes 801 defines a controllable phase modulation element 808, often referred to as a pixel, together with a transparent electrode 807 and an intervening liquid crystal material region disposed thereon. The effective pixel area, i.e., the filling rate, is the ratio of the optically active total pixels in consideration of the inter-pixel clearance 801a. By controlling the voltage applied to each electrode 801 with respect to the transparent electrode 807, the physical properties of the liquid crystal of each phase modulating element can be changed, thus providing a variable delay to the incident light incident thereto. By doing so, phase-limited modulation is applied to the wavefront, while no amplitude effect occurs.

The main advantage of using a reflective LCOS spatial light modulator is that the thickness of the liquid crystal layer can be halved compared to when a transmissive device is used. This greatly improves the switching speed of the liquid crystal (the key to the projection of video motion pictures). LCOS devices can also uniquely display large array of phase-limited elements within a small aperture. Small elements (typically less than about 10 microns) provide a practical diffraction angle (a few degrees), so that the optical system does not require a very long optical path.

It is easier to appropriately irradiate the small opening (several cm ² ) of the LCOS SLM than the opening of the large liquid crystal device. The LCOS SLM has a large aperture ratio, but has little dead space between pixels (since the drive circuit is buried under the mirror). This is an important issue in terms of reducing optical noise in the playback area.

Such a device typically operates at a temperature range of from about 10 DEG C to about 50 DEG C, and the optimal device operating temperature ranges from about 40 DEG C to 50 DEG C, depending on the LC configuration used.

Using a silicon backplane has the advantage that the pixels are optically flat, which is important for phase modulating devices.

It will be appreciated that the embodiments relate to reflective LCOS SLMs and that any SLM, including the transmissive SLM, can be used by one of ordinary skill in the art.

The present invention is not limited to the embodiments described, but extends to the full scope of the appended claims.

501: Light source
503: condensing lens
505: beam splitter
507: spatial light modulator
509: Beam synthesizer
521: first optical input
523: Second optical input

Claims (21)

A spatial light modulator comprising an array of phase modulating elements arranged to apply a phase delay distribution to incident light; And
A beam combiner comprising a first optical input for receiving spatially modulated light from the spatial light modulator, i.e., a space modulated light, and a second optical input having a real field of view,
And a near-eye device. The method according to claim 1,
Wherein the spatial modulated light comprises phase-only holographic domain data representing an image. 3. The method of claim 2,
Wherein the hologram area data is a Fourier hologram. The method of claim 3,
Wherein the spatial modulated light is adapted to allow a user's eye to see a holographic reconstruction of the image while performing a Fourier transform of the spatial modulated light. 3. The method of claim 2,
Wherein the hologram area data is a Fresnel hologram. 6. The method of claim 5,
Wherein the spatial modulated light is adapted to form a hologram reconstruction of the image on a replay plane in a near-field. 7. The method according to any one of claims 1 to 6,
Wherein said spatial modulated light further comprises phase limited hologram area data having a lensing effect. 8. The method of claim 7,
Wherein the lens effect is a negative lens effect. 9. The method according to any one of claims 1 to 8,
Wherein said spatial modulated light is diverging. 10. The method according to any one of claims 1 to 9,
Wherein said spatial modulated light further comprises phase limited hologram area data adapted to correct aberrations in other optical components of said spectacles apparatus. 11. The method according to any one of claims 1 to 10,
Wherein the beam synthesizer further comprises an optical output adapted to combine the light received at the first optical input with the light received at the second optical input. 12. The method according to any one of claims 1 to 11,
Wherein the light output is such that the light received at the first light input is at least partially overlaid with the light received at the second light input. 13. The method according to any one of claims 1 to 12,
Such that a user of the spectacled device is able to receive the light output from the beam synthesizer. 14. The method according to any one of claims 1 to 13,
Wherein the hologram reconstruction of the image augments the actual field of view. 15. The method according to any one of claims 1 to 14,
And a light source adapted to illuminate the spatial light modulator. 16. The method according to any one of claims 1 to 15,
Wherein the light source is arranged to illuminate the spatial light modulator with a plane wave of light. 17. The method according to any one of claims 1 to 16,
Wherein the spectacles-type apparatus is a goggle or a spectacle. A method of providing an augmented reality using a spectacles device,
Providing hologram data including phase-limited hologram area data representing an image;
Spatially modulating light with the hologram data to form spatially modulated light, i.e., spatially modulated light; And
Synthesizing the actual view and the space-modulated light using a beam synthesizer
Wherein the augmented reality providing method comprises: 19. The method of claim 18,
Wherein the hologram data further includes phase-limited hologram area data having a lensing effect. 20. The method according to claim 18 or 19,
Wherein the hologram area data is a Fourier hologram or a Fresnel hologram. 11. A method of providing augmented reality or a spectacles device substantially similar to that described with reference to the accompanying drawings.

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